1. Field of the Invention
The present invention relates to a silver halide photographic light-sensitive material and, more particularly, to a photographic light-sensitive material with a low fog and a high sensitivity.
2. Description of the Related Art
Methods of manufacturing and techniques of using tabular silver halide grains (to be referred to as "tabular grains" hereinafter) are disclosed in U.S. Pat. Nos. 4,434,226, 4,439,520, 4,414,310, 4,433,048, 4,414,306, and 4,459,353, JP-A-59-99433 ("JP-A" means Unexamined Published Japanese Patent Application), and JP-A-62-209445. Known advantages of grains of this type are an increase in sensitivity including an improvement in color sensitization efficiency obtained by sensitizing dyes, an improvement in a sensitivity/graininess relationship, an improvement in sharpness derived from specific optical properties of tabular grains, and an improvement in covering power.
In addition, JP-A-4-18242, JP-A-4-181939, and JP-A-4-190226 disclose that tabular grains in which the distribution of the silver iodide contents of individual grains is narrow have excellent photographic characteristics, such as a high sensitivity, a high gamma, and an improved rate of development.
In recent years, however, requirements for photographic silver halide emulsions have become strict more and more, and so a demand has arisen for a higher aspect ratio of tabular grains for the purpose of increasing the sensitivity, improving the sensitivity/graininess relationship, and increasing the sharpness.
It is, however, impossible to simultaneously achieve a high aspect ratio of tabular grains and a narrow distribution of the silver iodide contents of individual tabular grains. Therefore, the above requirements cannot be realized sufficiently by the conventional techniques.
JP-A-1-329231, on the other hand, discloses that tabular grains each containing 10 or more dislocation lines in its fringe portion have superior photographic characteristics, such as a high sensitivity, a good gradation, and an improved fog.
Introducing dislocation lines uniformly between grains at a high density is desirable in respect of concentration of latent image formation sites and effective chemical sensitization.
It is, however, impossible to realize both of a high aspect ratio of tabular grains and introduction of dislocation lines uniform between grains at a high density. The conventional techniques are unsatisfactory for this purpose.
The present invention aims at achieving both a high aspect ratio of silver halide tabular grains and a narrow distribution of the silver iodide contents of individual grains, and also aims to realize all of a high aspect ratio of tabular grains, introduction of dislocation lines uniform between grains at a high density, and a narrow distribution of the silver iodide contents of individual grains. More specifically, the present invention aims to perform uniform chemical sensitization for high-aspect-ratio silver halide tabular grains, which cannot be sufficiently done by the conventional techniques, i.e., aims to eliminate nonuniformity of chemical sensitization between grains.